This can be proven for any valid argument form using a truth table which shows that there is no situation in which there are all true premises and a false conclusion.
Founded in 1994, IntraLearn Software Corporation (ISC) is a pioneer of creating e-Learning and Knowledge Organization products for corporate enterprises, academic institutions, associations, government agencies and training suppliers.
Ameritech was one of the seven Regional Bell Operating Companies that was created following the breakup of the Bell System. Ameritech was acquired by SBC Communications in 1999 which subsequently acquired AT&T Corporation in 2006, becoming the present-day AT&T Inc.